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Engineering, Building, and Architecture

Not many museums collect houses. The National Museum of American History has four, as well as two outbuildings, 11 rooms, an elevator, many building components, and some architectural elements from the White House. Drafting manuals are supplemented by many prints of buildings and other architectural subjects. The breadth of the museum's collections adds some surprising objects to these holdings, such as fans, purses, handkerchiefs, T-shirts, and other objects bearing images of buildings.

The engineering artifacts document the history of civil and mechanical engineering in the United States. So far, the Museum has declined to collect dams, skyscrapers, and bridges, but these and other important engineering achievements are preserved through blueprints, drawings, models, photographs, sketches, paintings, technical reports, and field notes.

This ten-inch one-sided bamboo rule is coated with white celluloid only on the front. There is no indicator. The base has A, D, and K scales. The slide has B, CI, and C scales on one side and S, L, and T scales on the other side. The CI scale is numbered in red. The base is held together with a sheet of metal and with clear celluloid that has red hairlines at each end. The back of this metal and celluloid backing contains a chart on white plastic. The chart provides various relationships or conversions between the C and D scales as well as fundamental trigonometric relationships.

The instrument is marked in red at the top center of the base: FREDERICK POST CO. 1447. It is marked in black at the top right: HEMMI JAPAN. The Post logo (in red) appears at the right side of the slide. The back is stamped with the date code TD, indicating the rule was manufactured in April 1969. The style of the Post logo is consistent with this date.

The Frederick Post Company of Chicago imported slide rules made by the Japanese firm of Hemmi from about 1932 to the 1970s, with a brief interruption during World War II. Post sold Model 1447 from about 1949 to about 1971.

Chemist Albert S. Matlack donated this slide rule. He recalled that it was mainly used by his laboratory technician at the Hercules Research Center in Wilmington, Del.

Frank J. Thomas (1924–1976), a construction engineer from Topeka, Kan., invented the "Gradeulator" in the early 1970s. This circular slide rule was used to convert survey rod readings to sea level elevations, to determine the quantities of cut and fill required for earthwork, and to establish elevations for site grading and pavements.

The instrument has a square white plastic base with rounded corners. The base is covered with white cardboard that is marked with a circle divided into 100 equal parts, with each part divided into tenths. Four paper discs, each backed with metal, rest on the base. Each disc is divided along the edge into 100 equal parts, 50 for "cut" and 50 for "fill," and has three rings of numbers for 100-, 50-, and 25-foot grids. The second-largest disc is turned upsidedown and has ten square notches along its edge. The smallest disc has paper marked with scales on both sides of the metal, with the "cut" sections outlined in red ink. The instrument is held together with a metal screw and wing nut.

According to donor Rita Thomas Dukes, Thomas handmade and sold these instruments from his garage. The name "Gradeulator" was trademarked from November 11, 1975, to April 6, 1982 (serial no. 73013213, registration no. 1024537). In 1973, Thomas applied for a patent, which was issued in 1976.

This circular slide rule consists of a silver-colored metal dial, 8-1/2" wide, mounted on a silver-colored metal disc. Three oblong holes on the base disc permit the reading of trigonometric scales on a white celluloid and cardboard disc that is between the metal discs. The celluloid disc is marked: COPYRIGHTED (/) L. ROSS, SAN FRANCISCO (/) PATENTS PENDING.

On the front of the instrument, the top dial is divided along the outer edge into 400 equal parts. In each quadrant of the dial, the scale is marked from 100 to 1,000, with every tenth division marked. Inside of this scale, there is a spiral scale with 25 coils divided logarithmically from 0 to 1,000, making the rule equivalent to a linear slide rule about 50 feet long. These scales are marked in purple and are worn away in several places, including around much of the edge and underneath where the indicators rest.

Affixed to the center of the disc is a brown metal linear rule, 1-1/8" wide, marked with N, M (Sum), D (Difference), and Root scales. This rule is made of three pieces, but the center no longer slides. Also affixed to the center is a yellow celluloid hairline indicator, 3/4" wide, and a second yellow celluloid indicator, 1-1/2" wide. This indicator is marked on the left side by fours from 0 to 100, labeled Quadrants, and on the right side at varying intervals from 100 to 1,000, labeled Nos. It is attached to a metal handle lined with yellow-white celluloid. The handle is also attached to a pivot at the center back of the instrument. The handle is marked: THE ROSS (/) PRECISION COMPUTER (/) Computer Mfg. Co. (/) San Francisco. The handle has reminders for setting the device for multiplication, division, and proportion, and there is a thumbscrew for making adjustments.

The instrument also came with a loose, wedge-shaped piece of yellow celluloid with a hole at one end for attaching to the center of the computer. It is marked with the names of various trigonometric functions and various angles. The round part of the instrument fits into a black leather case with two snaps, stamped both inside and outside: x THE ROSS ÷ (/) PRECISION COMPUTER (/) COMPUTER MFG. CO. (/) SAN FRANCISCO U.S.A. (/) PAT. PEND. COPYRIGHTED. An instruction manual (1996.3077.02) and a letter and advertising literature (1966.3077.03) sent to the purchaser, Roy Kegerreis of New York, were received with this instrument. The letter is dated July 31, 1918, and the manual was copyrighted in 1919.

Louis Ross of San Francisco designed three circular slide rules in the 1910s: the Precision Computer, the Meridi-o-graph, and the Rapid Computer. Advertisements and reports of surviving instruments indicate that the Precision Computer varied in appearance and size.

The Computer Manufacturing Company sold the Precision Computer for $20.00. A clamp for mounting the rule above a desk sold separately for $2.50. The company claimed its customers included the Panama Canal Commission, DuPont Powder Works, and General Electric. The company's offices were originally located on 25 California Street in San Francisco; in 1921, the factory moved from 268 Market to 340 Sansome. The Sansome address is handwritten inside the instruction manual, suggesting Kegerreis learned about the computer in 1918 but did not purchase one until 1921.

Dr. Roy Kegerreis (1886–1968) obtained his BS in Electrical Engineering from The Ohio State University in 1907, his MS in Mathematics from Harvard, and his PhD in Physics from the University of Michigan in 1917. At the time he purchased this slide rule, he apparently was living in New York City. Kegerreis went on to get an MD in 1934, and he worked for many years as a radiologist. This slide rule was given to the Smithsonian by his daughter, in his memory.

In the late 19th and early 20th centuries, several circular slide rules were made to resemble pocket watches. Fowler & Co., of Manchester, England, was a particularly notable manufacturer of this type of slide rule. The company was in business from 1898 to 1988 and made a large variety of calculators, although the labor-intensive nature of its manufacturing process produced expensive instruments that never sold in large numbers.

This example is the "long scale" model, consisting of a metal case with a ring, two knobs, and two rotating paper discs covered with glass. The front has a short logarithmic scale and a long logarithmic scale, laid out in six concentric circles rather than in a spiral. These scales are rotated by the knob on the left. The glass is marked with two hairlines. The interior of the disc reads: FOWLER'S (/) LONG SCALE CALCULATOR (/) PATENT (/) FOWLER & Co MANCHESTER.

The other knob rotates the seven scales on the back of the instrument: multiplication and division, reciprocals, logarithms, square roots, logarithmic sines, logarithmic tangents, and a second scale for logarithmic sines. The interior is marked: FOWLER'S (/) CALCULATOR (/) PATENT (/) FOWLER & Co MANCHESTER. There is one hairline indicator on the glass. The slide rule is with a tarnished square metal case, lined with purple velvet. The outside of the case is engraved: Fowler's (/) CALCULATOR. The inside is stamped: Fowler & Co. (/) CALCULATOR (/) SPECIALISTS (/) Manchester (/) ENGLAND.

William Henry Fowler (1853–1932) and his son, Harold Fowler, took out several British patents for improvements to circular calculators between 1910 and 1924. The first Fowler calculator with two knobs on the rim was patented in 1914. In 1927, Fowler & Co. introduced the Magnum Long Scale Calculator, which extended the scale length to 50 inches. Thus, this example is dated between 1914 and 1927.

Charles Looney (1906–1987), the donor of this slide rule, catalogued engineering drawings and trade literature at the Smithsonian after he retired from the University of Maryland–College Park, where he served as chair of the Department of Civil Engineering. He also donated his library of books and pamphlets to the Museum.

This six-inch cylindrical slide rule consists of a chromium-plated holder, a metal cylinder that slides into the holder, and a black metal tube that fits around and slides up and down on the cylinder. The telescoping rule is ten inches long when extended and equivalent to a rectangular slide rule 66 feet in length. Two short white lines on the tube and a black mark on the chrome cap at the end of the cylinder serve as the indicator. A paper spiral logarithmic scale is attached to the top half of the holder. A second, linear and logarithmic, paper scale is attached to the cylinder. The logarithmic scales are used to multiply and divide, and the linear scale is used to find logarithms.

At the top of the cylinder is printed: PATENT No 183723. At the bottom of the cylinder is printed: OTIS KING'S POCKET CALCULATOR; SCALE No 430. The top of the scale on the holder is printed: SCALE No 429; COPYRIGHT. The bottom is printed: OTIS KING'S PATENT No 183723. The end of the holder is engraved: MADE IN (/) Y9481 (/) ENGLAND.

Otis Carter Formby King invented this form of slide rule in 1921, and Carbic Limited of London, England, manufactured it until 1972. The serial number, Y9481, suggests a date about 1965–1969 for this example. A collector of computing devices donated it to the Smithsonian.

See also 1987.0788.01 and 1989.3049.02. For documentation, see 1981.0922.10 and 1981.0922.11.

This ten-inch aluminum linear duplex slide rule is coated with white enamel and has aluminum endpieces. One side of the base has scales for sin/cos, tg/ctg (tangent/cotangent), DF, D, and the square root of 1 – x2 (a Pythagorean or P scale). On the slide are CF, CI, and C scales. The right end of the slide is marked: ECO BRA (/) Nr. 1611. The lower right corner of the base is marked: System (/) DARMSTADT. On the other side, the base has K, A, LL3, LL2, and LL1 scales. The slide has B, lg, and C scales. The numbers on the C, LL3, LL2, and LL1 scales are green, which is unusual. The indicator is plastic with aluminum edges. The letter Q is on the hairline on one side. On the other side, Q is on the hairline and W and PS are on shorter hairlines at the top of the indicator. These hairlines are for circle conversion and peripheral horsepower conversion, respectively.

The rule fits in a cardboard box covered with maroon synthetic leather. The top edge of the box is marked No. 1611. The front is marked with the Ecobra logo, and the back is marked MADE IN GERMANY.

Alwin Walther (1898–1967) of the Technische Hochschule in Darmstadt, Germany, developed the Darmstadt system of scales in 1934. His arrangement was aimed particularly at engineers. ECOBRA or Eco Bra was a brand name of Bayerische Reisszeugfabrik, a Nuremberg maker of drawing instruments that was purchased by Joseph Dietzgen in 1909. The company began producing slide rules before World War II, and after the war, Eugene Dietzgen Company of Chicago distributed ECOBRA rules in the United States. Metal rules were more popular in the United States than they were in Europe.

This six-inch cylindrical slide rule consists of a chromium-plated holder, a metal cylinder that slides into the holder, and a black metal tube that fits around and slides up and down on the cylinder. The rule is ten inches long when extended. Two short white lines on the tube and a black mark on the chrome cap at the end of the cylinder serve as the indicator. A paper spiral logarithmic scale is attached to the top half of the holder. A second, linear and logarithmic, paper scale is attached to the cylinder. The logarithmic scales are used to multiply and divide, and the linear scale is used to find logarithms.

At the top of the cylinder is printed: PATENT No 183723. At the bottom of the cylinder is printed: OTIS KING'S POCKET CALCULATOR; SCALE No 430. The top of the scale on the holder is printed: SCALE No 429; COPYRIGHT. The bottom is printed: OTIS KING'S PATENT No 183723. The end of the holder is machine engraved: MADE IN (/) Y5466 (/) ENGLAND.

Otis Carter Formby King invented this form of slide rule in 1921, and Carbic Limited of London, England, manufactured it until 1972. The Calculator Company served as Carbic's distributor in the United States. The 5-digit ZIP code on the mailing tube indicates this example was made after 1963. The serial number, Y5466, suggests a date around 1965–1969.

See also 1987.0788.01 and 1981.0922.09. The slide rule was received with a trifold instruction sheet, 1989.3049.03, and an advertising pamphlet, 1989.3049.04.

This duplex linear slide rule is made of mahogany coated with celluloid. There are DF and D scales on one side of the base and K, A, D, and L scales on the other side. There are CF, CIF, and C scales on one side of the runner and B, S, T, and CI scales on the other side. The scales are 20 inches long (the "5" in the model number refers to a rule with scales 20 inches long) and closely divided. The indicator is made of glass with a plastic frame.

The base is marked: KEUFFEL & ESSER CO.N.Y.; PAT. JUNE 5. ’00; DEC. 22. ’08; MADE IN U.S.A. The runner is marked: 4088-5. The serial number, on the other side of the runner, is: 72287. The slide rule is stored in a dark brown cardboard and glued leather box.

Keuffel & Esser published catalogs in 1899, 1902, 1905, 1909, 1912, 1915, 1921, 1927, and 1936. Model 4088-2 (8 in.) and 4088-3 (10 in.) slide rules first appeared in the 1913 printing of the 1912 catalog (facing p. 304). Model 4088-5 was first mentioned in 1921 (p. 239) and then again in 1927 (p. 302). In 1927 and in the 1930s (but not in 1921), the front of the runner had a B scale in addition to the S, T, and CI scales. By 1936, the 4088-5 was replaced by the N4088-5 (p. 314). On this basis, the rule dates from between 1922 and 1935. Additionally, the donor reported that he received the slide rule from a friend in about 1930. The instrument sold for $20.00 in 1927. Compare this object to MA*318476 and 1986.0790.02.

This rule consists of an outer wooden cylinder that slides up and down and rotates. Two brass rings lined with felt are inside this cylinder. The cylinder is covered with paper marked with a single spiral logarithmic scale graduated into 7250 parts and having a length, according to the maker, of 500 inches (nearly 42 feet). Inside the outer cylinder is a longer wooden cylinder, covered with paper marked with decimal, conversion, and sine tables. A solid mahogany handle is at one end. A third cylinder of brass is inside the instrument. A brass index is screwed to the top of the handle. A second, longer brass index is screwed to the mahogany base and marked with a scale of equal parts used in finding logarithms.

The tables on the middle cylinder include: decimal equivalents of feet and inches in feet; decimal equivalents of quarter weights and pounds in hundredweights; decimal equivalents of ounces and pounds in fractions of a pound; decimal equivalents of pounds, shillings, and pence in fractions of a pound; decimal equivalents of pence in shillings; days of the year as a fraction of the year; decimal equivalents of subunits of an acre; properties of various metals and woods; decimal equivalents of minutes of a degree in degrees; the Birmingham wire gauge; various conversion factors (mostly for weights and measures); and natural sines.

The outer, sliding cylinder is marked near the top: FULLERS SPIRAL SLIDE RULE. Near the bottom is marked: ENTD. STATS. HALL; STANLEY, Maker, LONDON. The bottom is stamped: 1099. The top of the long brass index is engraved: 1099 (/) 98. According to Wayne Feely, these numbers indicate the instrument has serial number 1099 and was made in 1898.

George Fuller, professor of civil engineering at Queen's University in Belfast, Ireland, patented this instrument in 1878. The Stanley firm made about 14,000 Fuller's spiral slide rules over nearly one hundred years. According to Boyd's Directory of the District of Columbia, Fred A. Schmidt, vendor of draftsmen's supplies, moved from 504 9th Street N.W. to 516 9th Street, with a branch at 1722 Pennsylvania Avenue, between 1895 and 1900.

According to the donor, this example came from the family of her first husband, Fred Robert Troll (1920–1971), a sanitary engineer who attended Columbia University. The original purchaser may have been his father, Frank Troll, or his uncle, who was an artist who traveled frequently.

This small (five-inch) one-sided slide rule is bamboo covered with white celluloid, with a clear celluloid and metal backing. A magnifying glass indicator has a metal frame. There are A and D scales on the base. The slide has B, CI, and C scales on one side and S, L, and T scales on the other side. The upper edge of the base has a four-inch ruler divided to thirty-seconds of an inch.

The back of the base is marked: THE FREDERICK POST CO. NO. 1441 (/) SUN (between two drawings of the sun) HEMMI JAPAN CF. A brown leather case is stamped on the flap: POST. Inside the case is stamped: MADE IN JAPAN and handwritten: R. FREEZE.

The instrument was made by the Hemmi Slide Rule Company of Tokyo, Japan, and sold by the Frederick Post Company of Chicago, Ill. In the 1930s and 1940s, Post sold this model for $2.70. The code CF on the slide rule indicates that this example was manufactured by Hemmi in June 1952. The donor, Richard Freeze, purchased it in Philadelphia around 1956–57, when he was a student at Drexel Institute of Technology (later Drexel University). He used it during classes in physics, mathematics, and industrial engineering. Later, he used it while working at a specialty chemical firm doing industrial engineering projects.